1. Field of the Invention
The present invention relates, in general, to fasteners and fastener caps used as washers for holding roofing paper, insulation wrap, and coverings to houses, lumber, and other articles in the construction industry, and, in particular, to stacks of such fastener caps that are loaded into magazines used in manual staplers and fastener applicators in the construction industry.
2. Description of Related Art
A conventional cap feeding device generally includes a cap container and a base having a channel. The base extends between the cap container and a position under the nose of the nail gun. Caps are fed into the channel of the base from the cap container and pushed to the position under the nose of the nail gun. When the gun is triggered, a nail penetrates and dislodges the cap under the nose of the nail gun and protrudes into the underlying roof structure. The feeding of the caps under the nose of the nail gun is coordinated with the ejection of the nails through the nose of the nail gun, so that a cap is placed under the nose of the gun before the gun is triggered to expel a nail. Well-known cap feeding and nailing devices, and stacked assemblies of roofing caps for use therein, are disclosed in Lamb, U.S. Pat. No. 7,090,455 (issued Aug. 15, 2006; hereinafter, the “Lamb patent”), fully incorporated by reference herein. The coaxially-stacked caps disclosed in this Lamb patent have the advantage that a stack of caps can be quickly loaded into the nailer's magazine as a stacked unit, rather than being inserted one-by-one into the magazine.
Many approaches are known in the prior art for quickly loading a stack of fastener caps into the nailer's magazine. Some approaches use an axially-disposed longitudinal rod or string to hold the stack of caps together while inserting the stack of caps into the nailer's magazine, and then the rod or string is removed, leaving the stack of caps in the magazine. Because there is nothing holding adjacent caps together after the rod or string is removed, these approaches have the disadvantage that, once inserted into the magazine, the caps cannot be removed without becoming unstacked, making reinsertion into the magazine very difficult as the caps have to be re-inserted one by one.
One embodiment of stacked caps disclosed in the Lamb patent, namely, the fifth embodiment shown in FIGS. 20-24 of the Lamb patent, has been shown to be a great improvement over the prior art. In this embodiment, a stacked assembly of caps is placed into a sled and then portions of the outer circumference of adjacent caps in the stack are melted together as by heating with hot air or by using a laser. As a bottommost cap is ejected from the magazine by a well-known pusher, the bottommost cap is sheared from the stack of caps and is then moved into position in the nailer and subsequently nailed. Because portions of the outer circumference of adjacent caps remain melted together until sheared apart during nailing, the stack of caps can readily be removed as a unit from the nailer's magazine and will still remain together as a stacked assembly of caps, thereby permitting easy reinsertion of the stack of caps into the magazine.
While this assembled stack of caps, with portions of the outer circumference of adjacent caps being melted together, has been shown to be a great improvement over the prior art, it is rather labor intensive to manufacture. The caps are individually molded using well-known injection molding techniques, and, when the halves of the injection mold separate and the caps are ejected from the mold using well-known ejector pins in the mold, the caps are ejected onto a screen or plate below the mold. The ejected caps then have to be manually gathered and inserted as a stack into a sled so that portions of the outer circumference of adjacent caps can be melted together as by heating with hot air or by using a laser, using the technique disclosed in the Lamb patent.
It is therefore desirable to have an improved assembly of stacked caps that do not have to be manually gathered and inserted as a stack into a sled for becoming joined together.
A prior art approach is known for joining a sequence of fastener caps in a linear string, as disclosed in Omli, U.S. Pat. No. 5,947,362 (issued Sep. 7, 1999; hereinafter the “Omli patent”), fully included herein by reference. FIG. 13 of the Omli patent shows a linear string of fastener caps that are molded as a continuous strip in which a connecting piece connects the perimeter of one cap to the perimeter of an adjacent cap. While such continuous linear strips of fastener caps have the advantage that the strip can be molded as a unit without excessive manual assembly, such continuous linear strips of fastener caps have the great disadvantage that they must be fed from a bulky spool, rather than from a compact magazine as preferred by the construction industry, thereby requiring a complex and bulky feed mechanism as disclosed in the Omli patent.
It is therefore desirable to have an improved assembly of stacked caps that can be injection molded as a unit, and which are stacked rather than being in a continuous linear strip.